Running Heavy Background process in struts 1.2

I am calling a heavy background process in action class. While the process is being completed i need to display a progress bar on jsp page and periodically check whether the process is completed and if yes then display result page.
Please help how it can be done with threads.

This really isn't a Struts issue and if you do some searching you will find that people have asked about this in the past. There are a number of ways to do what you ask and one solution can be found here.